What Will Be the Impact of Seven Billion People?

Photo: DonkeyHotey

On Halloween this year, the world’s population will hit seven billion — or so estimates the United Nations Population Fund. Spooky, considering we hit six billion only a little more than a decade ago. Elizabeth Kolbert offers a brief history of population growth in a recent New Yorker article:

Depending on how you look at things, it has taken humanity a long time to reach this landmark, or practically no time at all. Around ten thousand years ago, there were maybe five million people on earth. By the time of the First Dynasty in Egypt, the number was up to about fifteen million, and by the time of the birth of Christ it had climbed to somewhere in the vicinity of two hundred million. Global population finally reached a billion around 1800, just a couple of years after Thomas Malthus published his famous essay warning that human numbers would always be held in check by war, pestilence, or “inevitable famine.”

Of course, we all know that Malthus was a little off the mark. But as the world’s population continues to grow (to perhaps 10 billion and growing by 2100), Kolbert raises concerns about the planet’s ability to sustain all that life: “As many, including Bill Gates, have pointed out, just to keep per-capita food production constant in the coming decades will require a second ‘green revolution.'”  Part of what made the first green revolution possible was a sharp increase in the use of phosphorus-rich fertilizers,” she writes.  “Thanks to this increased use, experts say, reserves of phosphorus are now being exhausted…Other essential commodities that could similarly run short include oil, water, and arable land.”